Digital three-dimensional manufacturing, also known as digital additive manufacturing, is a process of making a three-dimensional solid object of virtually any shape from a digital model. Three-dimensional printing is an additive process in which one or more printheads eject successive layers of material on a substrate in different shapes. The substrate is either supported on a platform that can be moved three dimensionally by operation of actuators operatively connected to the platform. Additionally or alternatively, the printhead or printheads are also operatively connected to one or more actuators for controlled movement of the printhead or printheads to produce the layers that form the object. Three-dimensional printing is distinguishable from traditional object-forming techniques, which mostly rely on the removal of material from a work piece by a subtractive process, such as cutting or drilling.
In some three-dimensional object printers, one or more printheads having an array of nozzles are used to eject material that forms part of an object, usually called build material, and to eject material that forms support structures to enable object formation, usually called support material. Most multi-nozzle printheads contain cavities that are filled with the type of material to be ejected by the printhead. These cavities are pressurized to eject drops of material, but they can only print materials having a very limited range of viscosities. Typically, these materials have a viscosity in the 5-20 cP range. Some materials considered ideal for manufacturing objects have viscosities that greater than those of materials that can be used in currently known printheads.
To overcome the limitations associated with high viscosity materials, single nozzle printheads have been used to eject materials to form objects. These single nozzle printheads are too large to be manufactured as arrays. Consequently, the productivity of the objects that can be produced by these printheads is limited. Printheads capable of enabling higher viscosity fluids to flow through the channels in a printhead and be ejected from the printheads would be advantageous.